leetcode -- 322

322. Coin Change

Problem Description

You are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you need to make up that amount. If that amount of money cannot be made up by any combination of the coins, return -1.

Example 1:

Input: coins = [1, 2, 5], amount = 11
Output: 3
Explanation: 11 = 5 + 5 + 1

Example 2:

Input: coins = [2], amount = 3
Output: -1

Note:

You may assume that you have an infinite number of each kind of coin.

Solution Method

int coinChange(int* coins, int coinsSize, int amount)
{
    // 和簡單的相比，coins數額不確定，consSize不確定
    int dp[amount+1];
    dp[0] = 0;
    for (int i = 1; i < amount+1;i ++)
    {
        dp[i] = 0x7fffffff;
        for (int j = 0;  j < coinsSize; j ++)
        {
            if (i >= coins[j])
                dp[i] = (dp[i] < dp[i-coins[j]] + 1) ? (dp[i]) : (dp[i-coins[j]] + 1);
        }
    }
    return dp[amount] == 0x7fffffff ? -1: dp[amount];
}